PAREIRA 243 



Inner Structure. Epicarp of a single row of nearly cubical 

 cells; a broad layer of thin-walled tangentially elongated cells, 

 having thin, brownish walls and a brownish granular content, the 

 latter becoming reddish-brown with solutions of the alkalies; a layer 

 of reddish-brown elongated cells in among which are distributed the 

 | small fibro vascular bundles; a few rows of light yellow, porous cells; 

 endocarp composed of thick-walled, strongly lignified sclerenchy- 

 matous fibers which ramify among each other; endosperm of large 

 polygonal cells, having thin walls and containing an oily cytoplasm 

 and large protein grains. In the cells of the endosperm and in large 

 diaphragms formed by the separation of the cells, occur small acicular 

 or prismatic crystals, frequently united to form aggregates. These 

 crystals are of the fixed oil and are insoluble in water and dilute 

 acids, but soluble in ether and solutions of the alkalies. 



Constituents. The seeds contain 1.5 per cent of Picrotoxin 

 (cocculin), a neutral principle which forms colorless, inodorous 

 prisms, having a bitter taste and very toxic properties. From 11 

 to 25 per cent of a fixed oil consisting chiefly of stearic and oleic acids. 

 They also contain small quantities of resin, wax, gum and starch. 

 The pericarp contains 2 tasteless, non-toxic, crystallizable alkaloids, 

 viz., menispermine and taramenispermine. 



PAREIRA. Pareira Brava. The root of Chondrodendron tomen- 

 tosum (Fam. Menispermacese), a perennial climber indigenous to 

 Brazil and Peru. The commercial article is exported from Rio 

 Janeiro. 



Description. (Fig. 110.) Nearly cylindrical, more or less tor- 

 tuous, cut into pieces up to 20 cm. in length, and varying from 1 to 6 

 cm. in diameter; externally brownish-black to blackish-brown with 

 tranverse ridges and knot-like projections and occasionally fissures, 

 and longitudinally wrinkled or even furrowed; hard, heavy and 

 tough; when freshly cut having a waxy luster; the transverse sur- 

 faces exhibiting several successive excentral and distinctly radiate 

 concentric zones of projecting secondary fibrovascular bundles, 

 each 2 to 4 mm. wide and separated by distinct concentric zones of 

 parenchyma and stone cells; odor slight; taste very bitter. 



The pieces of stem which are sometimes admixed with the drug 

 and which should be rejected are deeply furrowed, usually covered 

 with grayish foliaceous patches of lichens bearing their blackish 

 apothecia, and are more of a grayish-yellow color internally, dis- 

 tinctly woody and without a waxy luster. 



Inner Structure. Transverse sections show an anomalous struc- 

 ture, consisting of eight or more concentric or excentric rings, each 



